Background and Objectives: This systematic review with meta-analysis aimed to evaluate and synthesize the scientific evidence of interventions for sleep disorders on sleep quality, cognitive function, and quality of life in older adults with mild cognitive impairment (MCI). Materials and Methods: A systematic literature search was conducted between April 2024 and January 2025 using the Core Collection of seven generic databases: PubMed, EBSCOhost, CINAHL Complete, Cochrane, Scopus, ProQuest, and Web of Science. The PRISMA, RoB 2.0, and GRADEpro tools assessed the evidence’s methodological quality and certainty. The protocol was registered in PROSPERO (CRD42024558406). Results: A total of 2815 records were found in the databases, of which eight studies were analyzed using the PICOS format. There was a significant large effect (p = 0.005) in favor of the experimental group compared to the control group in the Sleep Quality Index (p = 0.005). No significant differences were reported for the other variables studied. Conclusions: Interventions for sleep disorders in older people with MCI aimed at improving sleep quality demonstrated significant effects assessed with PSQI. Individual results demonstrated limited effects on cognitive function and quality-of-life assessments.